Pitfalls with oral histories and memoirs

I’m currently revisiting an Oregon Trail pioneer couple in my wife’s tree to see if I can break through that brick wall. The pair were part of the first wagon train to Oregon, and their children preserved quite a few stories about the journey, but I know almost nothing about their parents.
That’s made me think about how to use this type of primary source document, including its biggest peril: the potential unreliability of the source. Perhaps their memory is faulty, or they embellished a story to make it more compelling, or perhaps they deliberately hid some details that they found embarrassing.
When I look at oral and written history, I try to break the information into two categories:
First are genealogical data points such as birth and marriage years. I use this is a roadmap to find a primary source such as a parish register.
Second are personal stories that probably can’t be verified but can flesh out their lives.
As to reliability, I try to consider the human risk factors. The larger the gap between when the story was written down or told, and when the events happen; or the more people retelling the story, the more skeptical I am.